.jump_span{
    width: 20px;
    height: 15px;
    overflow: hidden;
    overflow: hidden;

}
.jump_span li{
    height: 20px;
    width: 3px;
    background-color: springgreen;
    list-style: none;
    float: left;
    margin-left: 3px;
    overflow: hidden;
    
}
.jump_span li:nth-of-type(1){
    animation: li_one linear infinite 600ms;
}
.jump_span li:nth-of-type(2){
    animation: li_two linear infinite 600ms;
}
.jump_span li:nth-of-type(3){
    animation: li_three linear infinite 600ms;
}
@keyframes li_one {
  0% {transform: translateY(0);}
  25%{transform: translateY(10px);}
  50% {transform: translateY(20px);}
  75% {transform: translateY(10px);}
  100% {transform: translateY(0px);}
}
@keyframes li_two {
    0% {transform: translateY(10px);}
  25%{transform: translateY(20px);}
  50% {transform: translateY(10px);}
  75% {transform: translateY(0px);}
  100% {transform: translateY(10px);}
}
@keyframes li_three {
    0% {transform: translateY(20px);}
  25%{transform: translateY(10px);}
  50% {transform: translateY(0px);}
  75% {transform: translateY(10px);}
  100% {transform: translateY(20px);}
}